Generally, in an electrophotographic image forming apparatus, such as a laser printer or the like, a developer cartridge filled with a toner is mounted so as to be freely attached to or detached from it.
In such a developer cartridge, a filling chamber and a developing chamber are formed. In the filling chamber, a toner is filled, and a rotationally driven agitator is provided. In addition, in the developing chamber, a feeder roller, a developer roller, and a layer pressure regulating plate are provided. The feeder roller and the developer roller are disposed opposite to each other such that they come into contact with each other, and the layer pressure regulating plate contacts a surface of the developer roller with pressure.
In addition, the developer cartridge is mounted in the laser printer. If a power output from the laser printer is input to the developer cartridge though a gear connection or the like, the agitator is driven to rotate, so that the toner filled in the filling chamber is carried to the developing chamber. Then, in the developing chamber, the toner is supplied to the developer roller by the rotation of the feeder roller. At this time, the toner is subjected to frictional charging between the feeder roller and the developer roller. Further, when the developer roller rotates, the toner loaded on the surface of the developer roller enters between the layer pressure regulating plate and the developer roller and then carried on the surface of the developer roller that is a thin layer having a predetermined thickness.
In addition, in the laser printer, the developer cartridge is disposed such that the developer roller and the photosensitive drum are opposite to each other. When the toner, which has been carried on the surface of the developer roller that is the thin layer, is opposite to the photosensitive drum, the toner develops an electrostatic latent image so as to form a visible image. Then, the visible image is transferred to the paper by the rotation roller, and thus a predetermined image is formed on the paper.
Further, as described above, the developer cartridge is mounted on the laser printer, so that the toner accommodated in the filling chamber is consumed. In addition, when the toner is empty, the laser printer displays a message indicating that the toner is empty so as to advise a user to exchange the used developer cartridge with a new developer cartridge. Therefore, the user removes the used developer cartridge from the printer, and mounts a new developer cartridge in the printer.
However, in recent years, in the exchange of this developer cartridge, generally, the used developer cartridge is not discarded in view of recycling, but a new toner is refilled in the used developer cartridge so as to be reused.
For example, a technology about a determining device and a determining method is disclosed in JP-A-2004-054243. Specifically, according to the technology disclosed in JP-A-2004-054243, a toner color of a toner cartridge, a year, month, and date when the toner cartridge is manufactured, the number of printed paper, and the number of reused toner cartridge are read out from a storing element provided in the toner cartridge (developer cartridge). Then, using a condition value corresponding to the read toner color, the determining device determines whether the toner cartridge is reused or not reused. In addition, a color of the filled toners determined when it is determined that the corresponding toner cartridge can reused, so that it can be easily determined whether the toner cartridge can be reused and the effective utilization of the toner cartridge can be achieved.
As such, by determining whether the toner cartridge can be reused by the determining element, problems can be solved, in which the difference is generated between determining references of people and a time or effort is required for performing the determination.